JPH0890094A - Device for forming drawing product with step - Google Patents

Abstract

PURPOSE: To provide a forming device of a drawing product with steps which can efficiently form a deep drawing product with steps of a large difference in level of a sheet metal without generating wrinkles or cracks on the body with one stroke of a punch. CONSTITUTION: This device is installed with a die side blank wrinkle suppressing mechanism 2 having an up and down movable wrinkle suppressor 20 inside a hollow space 10 of a lower die 1 installed with a sheet holding face 11 on the circumference, on an upper die side, it is installed with a blank holder 5 which clamps the peripheral side of a sheet metal together with the sheet holding face 11, a punch 4 which is able to advance or retire to the hollow space inside the wrinkle suppressor 20, and a punch side blank holding mechanism 6 having an up and down movable blank holder 60 which is opposed to the wrinkle suppressor 20 and which clamps the sheet metal W together with the wrinkle suppressor 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming step drawn products from thin sheets.

[0002]

2. Description of the Related Art It is well known that deep drawing of container-shaped, cup-shaped products and the like is performed from a thin plate such as a steel plate and a stainless steel plate, but a step portion is formed on one side, both sides or the entire circumference of the side wall. In the case of a deformed product shape such as having a wrinkle, wrinkles are likely to occur on the stepped portion. As a measure against this,
Conventionally, molding is performed by providing a bead on the wrinkle holding surface. The applied tension due to this bead has a certain effect for preventing wrinkles, but on the other hand, since the flow of the material is restrained and pulled, cracks are likely to occur. This becomes remarkable especially when the step difference (distance from the step surface to the bottom) of the step portion is large, and cracks frequently occur in the molding method using the drawing bead. In order to avoid this, it is necessary to perform multi-step molding such as forming the convex portion as the first step and forming the outer peripheral portion as the second step, which causes a problem that productivity is reduced and cost is increased. It was

The present invention was devised to solve the above-mentioned problems, and an object of the present invention is to provide a stepped deep-drawing product of a thin plate having a large step to prevent body wrinkles and wrinkles. An object of the present invention is to provide a step drawing product forming apparatus capable of forming efficiently in one stroke of a punch.

[0004]

In order to achieve the above object, the present invention provides a die side wrinkle holding mechanism having a vertically movable wrinkle holding member in the space of a lower die having a plate holding surface around the space. A blank holder for pressing the peripheral portion of the thin plate with the plate pressing surface on the upper mold side, a punch capable of advancing and retracting with respect to the inner space of the wrinkle pressing member, and the wrinkle pressing member facing each other. And a punch-side wrinkle holding mechanism having a vertically movable wrinkle holding device for sandwiching a thin plate. The movable die may be provided only on one side of the die hole, may be provided on both sides of the die hole, or may be provided on the entire circumference of the die hole. The die side wrinkle holding mechanism and the punch side wrinkle holding mechanism are controlled so that the wrinkle holding force by the hydraulic ram and the die side wrinkle holding mechanism hydraulic ram is greater than the wrinkle holding force by the punch side wrinkle holding mechanism hydraulic ram. And a hydraulic circuit that operates.

[0005]

When the punch 4 is lowered while the blank plate 5 is pressed by the blank holder 5, the wrinkle presser 60 contacts the thin plate region inside the nipping position between the blank holder 5 and the plate pressing surface 11. At this position, the crease retainer 20, 20 on the die side
Since the punch 4 is pushed up, the thin plate region is pinched by the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60 by the lowering of the punch 4, and in this state, the punch 4 is continuously lowered to cause the punch 4 to wrinkle retainer 20, When the thin plate W enters the inside of the wrinkle retainer 20, 20 while being bent by the upper edge shoulders of the wrinkle retainer 20, 20, the thin plate W is drawn into the inside of the wrinkle retainer 20, 20.
1 and a small-sized side wall W2 subsequent thereto are formed. At the time of this forming, the thin plate W is pressed in the region in the immediate vicinity of the punch 4 and the peripheral region, so that flange wrinkles do not occur and body cracks do not occur. Wrinkle retainer 6 as punch 4 descends
0 and 60 retreat (raise) along the outside of the punch 4 and are integrated with the punch 4, and the pressing force of the wrinkle pressers 60 and 60 becomes the same as the lowering force of the punch 4, and the lowering force of the punch 4 wrinkles. It is much larger than the wrinkle holding force of the presser foot 20, 20. Therefore, the wrinkle pressers 20, 20 are forcibly pushed down as the punch 4 descends while sandwiching the thin plate with the wrinkle pressers 60, 60. Therefore, the thin plate is bent by the upper edge of the space portion 10 and drawn in between the outside of the wrinkle retainers 60, 60 and the space portion wall, and the wrinkle retainers 20, 20 and the wrinkle retainer 6
0 and 60 form a horizontal step W3, and the outer surfaces of the creasing presses 20 and 20 form a large-sized side wall W4. The punch 4 is formed when the punch 4 reaches a predetermined stroke. Is completed. In this step forming process, the thin plate portion in the region of the step W3 is pinched by the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60, and the wrinkle retainer for forming the large-sized side wall W4 is the blank holder 5. Since the plate pressing surface 11 is used, the material flow is smooth, and the large-sized side wall W4 is not cracked. Further, since the restraining force by the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60 acts, the pulling force does not act on the small-sized side wall W2. Therefore, the small-sized side wall W2 does not crack.

[0006]

The present invention will be described in detail below with reference to the accompanying drawings. FIGS. 1 to 4, 5 and 6 show an embodiment of a step drawn product forming apparatus according to the present invention, and FIGS. 7 and 8 show step drawn products obtained according to the present invention. FIG. 4 shows an embodiment applied to the molding of the products of FIGS. 7 and 8 (b). Reference numeral 1 denotes a lower die, which has a block shape and is provided with a space portion 10 having at least one side larger than the outer diameter dimension of the punch in the central portion, and the periphery of the thin plate W is placed outside the space portion 10. A plate pressing surface 11 is provided.
Reference numeral 2 denotes a die-side wrinkle holding mechanism installed near the inner wall 100 of the space 10. In this embodiment, one die-side wrinkle holding mechanism 2 is installed on each of the left and right sides of the space portion 10, and the back surface of each die-side wrinkle holding mechanism 2 is in sliding contact with or close to the inner wall 100 of the space portion 10. It comprises a block-shaped or plate-shaped vertically movable wrinkle retainer 20, and a single or a plurality of hydraulic rams 21 having a piston rod 210 connected to the lower portion of the wrinkle retainer 20. Each hydraulic ram 21 includes a hydraulic pump 220, a check valve 221, and a hydraulic circuit 22 provided downstream of the check valve 221 and having a pressure control valve 222 for adjusting a die side wrinkle holding force, which will be described later, as shown in FIG. It is connected.

The upper die 3 is a slide table which is moved up and down by a punch ram 41 provided in the press body.
(Inner slide) 4 ', punch 4 fixed to a slide table portion corresponding to the inside of the wrinkle retainer 20 directly or via a mounting bracket, and the plate retainer surface outside the slide table 4'. A blank holder 5 having a ring shape facing 11 is provided, and a punch side wrinkle holding mechanism 6 provided between the blank holder 5 and the punch 4 so as to face the die side wrinkle holding mechanism 2. The blank holder 5 is fixed to the outer slide 50 like a known one, and the outer slide 50 is moved up and down by a blank holder ram 51 provided in the press body. Punch side wrinkle holding mechanism 6
In this example, one punch is installed on each of the left and right sides of the punch 4, and each punch-side crease presser mechanism 6 is a block-shaped or plate-shaped upper and lower pair which is paired with the crease presser 20 of the die-side crease presser mechanism 2. Movable wrinkle foot 60 and lower wrinkle foot 60
A hydraulic ram 61 or a plurality of hydraulic rams 61 having a piston rod 610 connected thereto. The wrinkle retainer 60 has an inner contour that matches the side wall contour of the punch 4, and is configured to be guided along the side wall of the punch 4. The wrinkle retainer 60 is provided on the lower surface of the slide table 4'corresponding to the side wall base of the punch 4. Receiving surfaces 40, 40 which can be brought into close contact with the upper part are provided. As shown in FIG. 1, each hydraulic ram 61 has a hydraulic circuit 62 including a hydraulic pump 620, a check valve 621, and a pressure control valve 622 that is located downstream of the check valve 621 and adjusts a punch-side wrinkle holding force, which will be described later. It is connected to the. If the output of the hydraulic ram 61, that is, the punch side wrinkle pressing force is BHF2, and the output of the hydraulic ram 21, that is, the die side wrinkling pressing force is BHF3, the present invention is BHF2 <BH.
The relationship is F3. This is the pressure control valve 222,
It is realized by the set pressure by 622.

FIGS. 5 and 6 are for obtaining a product having a step W3 over the entire circumference as shown in FIG. 8 (c). The crease retainer 20 of the die side crease retainer mechanism 2 and the punch side crease retainer mechanism 6 are shown. The wrinkle retainer 60 has a ring shape having holes 200 and 600 having a contour corresponding to the cross-sectional contour of the punch 4 in the center, and the wrinkle retainers 20 and 60 are supported by a plurality of hydraulic rams 21 and 61, respectively. Has been. Since the other mechanism is similar to that of the embodiment shown in FIGS. 1 to 4, the same parts are designated by the same reference numerals and the description thereof will be omitted. The present invention can be applied not only to die molding but also to counter-hydraulic molding. To perform this counter-hydraulic molding, as shown in FIG.
The liquid lead-in / out passage 11 may be connected to the bottom of 0, and the liquid lead-in / out passage 11 may be connected to the pump 120 and the counter hydraulic circuit 12 having the relief valve 121. In this case, the counter hydraulic pressure F acts on the wrinkle retainer 20 as a lifting force at the time of molding, so that BHF3 + F> BHF2 may be set.

In order to obtain a product W'having a bottom W1 and a step W3 lower than this as shown in FIG.
It is sufficient to eliminate the die side wrinkle holding mechanism 2 and the punch side wrinkle holding mechanism 6 on one side in FIG. 4 and narrow the space portion 10 by that portion. In addition, as shown in FIG. 8D, the rectangular bottom W1
In order to obtain a product W'having a step W3 and a side wall W4 with a circular contour below the side wall W2 and the side wall W2, the contour of the space 10 is circular, the cross sectional contour of the punch 4 is rectangular, and the die side wrinkle holding mechanism 2 is used. The holes 200 and 600 of the wrinkle presser 20 and the wrinkle presser 60 of the punch side wrinkle presser mechanism 6 may be formed in a shape corresponding to the contour of the punch. Further, as shown in FIG. 8 (e), in order to obtain a product W ′ having a step W3 and a side wall W4 having a rectangular contour below a bottom W1 and a side wall W2 having a circular contour, the contour of the space portion 10 is made rectangular and the punch 4 is used. The cross-sectional contour of the wrinkle may be circular, and the holes 200 and 600 of the wrinkle retainer 20 of the die side wrinkle retainer mechanism 2 and the wrinkle retainer 60 of the punch side wrinkle retainer mechanism 6 may have a shape corresponding to the contour of the punch. In the embodiment, the hydraulic rams 61, 61 of the punch side wrinkle pressing mechanism 6 are provided on the slide table 4 ', but the invention is not limited to this and may be provided on the punch 4. In this case, the slide table 4'also becomes a part of the punch 4 in FIG. 1, and the receiving surfaces 40, 40 are provided at the base of the part functioning as a punch. In any case, the slide table 4'and the punch portion corresponding to the slide table 4'may have a hollow structure in which reinforcing bones are assembled instead of the solid structure.

[0010]

Next, the operation of the embodiment of the present invention will be described. At the time of molding, the hydraulic circuit 22 is operated to supply the hydraulic pressure to the piston side of the hydraulic rams 21 and 21, and the wrinkle retainer 2
0 and 20 are pushed up to be aligned with the plate pressing surface 11 of the lower mold 1 in the same plane. In this state, the thin plate W is placed, and the outer slide 50 is lowered to clamp the peripheral portion of the thin plate W by the blank holder 5 and the plate pressing surface 11. This is the state of FIG. 1, in which the punch 4 is located above the thin plate W, and the hydraulic circuit 62 is provided in the hydraulic ram 61 of the punch side wrinkle holding mechanism 6.
Since the pressure oil is supplied from the wrinkle retainers 60, 60, the wrinkle retainers 60, 60 are held flush with the tip of the punch 4 or at a position appropriately protruding from the tip level of the punch 4.

Next, when the punch ram 41 is actuated, the slide table 4'and the punch 4 are lowered, whereby the wrinkle retainer 60 comes into contact with the thin plate region inside the nipping position between the blank holder 5 and the plate retaining surface 11. As described above, the wrinkle pressers 20 and 20 are pushed up to this position, and the wrinkle presser force BHF2 of the wrinkle pressers 60 and 60 is the wrinkle presser 2
The wrinkle holding force BHF3 of 0, 20 and BHF2 <BHF3. Therefore, when the punch 4 descends, the thin plate region is pinched by the wrinkle retainers 20, 20 and the wrinkle retainer force BHF2 by the wrinkle retainers 60, 60. In this state, the punch 4 continues to descend to cause the punch 4 to wrinkle retainer 20, 20
When the thin plate W enters the inside of the wrinkle retainers 20, 20 while being bent by the upper edge shoulders of the wrinkle retainers 20, 20, the thin plate W is drawn into the inside of the wrinkle retainers 20, 20, and as shown in FIG.
2 are molded. At the time of this forming, the thin plate W is pressed in the region in the immediate vicinity of the punch 4 and the peripheral region, so that flange wrinkles do not occur and body cracks do not occur.

In this way, as the punch 4 descends, the piston rods 610 and 61 of the wrinkle retainers 60 and 60 are
0 retreats, so wrinkle presser 60, 60 is punch 4
The upper surface of the wrinkle retainers 60, 60 comes into close contact with the step portions 40, 40 by retracting (raising) along the outer side of the. Wrinkle foot 6 by this
0 and 60 are integrated with the punch 4, and the pressing force of the wrinkle retainers 60 and 60 is the same as the descending force of the punch 4, and the descending force of the punch 4 is much larger than the wrinkle retaining force BHF3 of the wrinkle retainers 20 and 20. . Therefore, the wrinkle pressers 20, 20 are forcibly pushed down as the punch 4 descends while sandwiching the thin plate with the wrinkle pressers 60, 60. Therefore, the thin plate is bent by the upper edge of the space portion 10 while the wrinkle retainer 60,
It is drawn between the outside of 60 and the space wall, and as shown in FIG. 4, the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60 form a horizontal step W3 and the wrinkle retainer 20,
A large-sized side wall W4 is formed by the outer side surface of 20 and the space wall, and the molding is completed when the punch 4 reaches a predetermined stroke. In this step forming process, the thin plate portion in the region of the step W3 is pinched by the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60, and the wrinkle retainer for forming the large-sized side wall W4 is the blank holder 5. The flow of material is smooth because it is performed by the plate pressing surface 11, and the large-sized side wall W
The crack of 4 does not occur. Further, since the restraining force by the wrinkle retainers 20, 20 and the wrinkle retainers 60, 60 acts, the pulling force does not act on the small-sized side wall W2. Therefore, the small-sized side wall W2 does not crack. Therefore, even if the step is large, it can be molded into a good shape without defects as shown in FIG. The product of FIG. 7 shows an actual product, and the size of the large-sized side wall W4 is 100 × 130 mm, the protruding size of the step portion is 85 mm, and the step is 20 mm.

In order to perform the counter hydraulic forming using the present invention, the space portion 10 is formed by the counter hydraulic circuit 12 in the state of FIG.
Fill with oil or water. This way,
As the counter hydraulic pressure is generated in the space 10 by lowering the punch 4 as described above, the thin plate is brought into close contact with the punch 4 by the counter hydraulic pressure, and the bottom portion W1 and the small side wall W2 following the bottom portion W1 have good dimensions and shapes. Is molded into. Also wrinkle presser 60,6
When the upper surface of 0 comes close to the step portions 40, 40 and is integrated with the punch 4, if the hydraulic pressure of the space portion 10 is released, the wrinkle retainer 20,
Since the pushing-up force due to the counter hydraulic pressure acting on 20 is lost, the wrinkle retainers 20, 20 are lowered by the lowering of the punch 4, and the step portion is die-molded as described above.

[0014]

According to the present invention described above, the die side wrinkle holding mechanism provided with the vertically movable wrinkle holding member 20 in the space 10 of the lower die 1 in which the plate holding surface 11 is provided around the space 10. 2, a blank holder 5 for pressing the peripheral portion of the thin plate with the plate pressing surface 11 on the upper die side, and a punch 4 capable of advancing and retracting with respect to the space inside the wrinkle pressing member 20.
And the punch-side wrinkle presser mechanism 6 having the vertically movable wrinkle presser 60 that sandwiches the thin plate W between the wrinkle presser 20 and the wrinkle presser 20. It is possible to perform the molding in one stroke without generating, and since the structure is simple and the operation direction is the same as the ascending and descending direction of the punch, it is possible to obtain excellent effects such as easy control.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an embodiment of a step drawing product molding apparatus according to the present invention in a molding start state.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a vertical sectional side view showing a state during molding.

FIG. 4 is a vertical cross-sectional side view showing a state at the end of molding.

FIG. 5 is a plan view of a lower mold showing another embodiment of the present invention.

FIG. 6 is a vertical sectional side view showing the embodiment of FIG. 5 in a molding start state.

7 is a perspective view of a product obtained in the embodiment of FIGS. 1 to 4. FIG.

FIG. 8 is a perspective view showing an example of the shape of a product molded according to the present invention.

[Explanation of symbols]

 1 Lower mold 2 Die side wrinkle presser mechanism 3 Upper mold 4 Punch 5 Blank holder 6 Punch side wrinkle presser mechanism 10 Space part 20 Wrinkle presser 21,61 Hydraulic ram 22,62 Hydraulic circuit 60 Wrinkle presser

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B21D 24/04 D 8315-4E

Claims (6)

[Claims] 1. A die side wrinkle holding mechanism 2 provided with a vertically movable wrinkle holding member 20 is provided in the space 10 of a lower die 1 having a plate holding surface 11 provided around the space 10 and is provided on the upper die side. Is a blank holder 5 that presses the peripheral portion of the thin plate with the plate pressing surface 11, a punch 4 that can move forward and backward with respect to a space inside the wrinkle presser 20, and the wrinkle presser 20 that faces the thin plate. A stepped drawn product forming apparatus, comprising: a punch-side wrinkle holding mechanism 6 having a vertically movable wrinkle holding member 60 for holding W. 2. A die side wrinkle holding mechanism 2 and a punch side wrinkle holding mechanism 6 have hydraulic rams 21 and 61, respectively, and a wrinkle holding force BHF2 by the hydraulic ram 21 of the die side wrinkle holding mechanism 2 is the punch side wrinkle holding mechanism 6. Hydraulic circuit 2 for controlling so as to be larger than the wrinkle pressing force BHF3 by the hydraulic ram 61 of
2. The step drawing product forming apparatus according to claim 1, further comprising: 3. A wrinkle retainer 60 of a punch side wrinkle retainer mechanism 6 on the base end of the punch 4 or the lower surface of a slide to which the punch 4 is attached.
The step drawing product forming apparatus according to claim 1 or 2, further comprising a receiving surface 40 for the. 4. The step drawing product forming apparatus according to claim 1, wherein the die side wrinkle pressing mechanism 2 is provided on both sides of the space 10. 5. The step drawing product forming apparatus according to claim 1, wherein the die side wrinkle holding mechanism 2 has an annular shape. 6. The step drawing product forming apparatus according to claim 1, wherein the die side wrinkle holding mechanism 2 is provided only on one side of the space portion 10.